| MAD-MAX TRANSCRIPTIONAL REPRESSION IS MEDIATED BY TERNARY COMPLEX-FORMATION WITH MAMMALIAN HOMOLOGS OF YEAST REPRESSOR SIN3 |
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| Author(s): AYER DE, LAWRENCE QA, EISENMAN RN |
| Source: CELL Volume: 80 Issue: 5 Pages: 767-776 Published: MAR 10 1995 |
| Times Cited: 426 References: 61 |
| Abstract: The bHLH-ZIP protein Mad heterodimerizes with Max as a sequence-specific transcriptional repressor. Mad is rapidly induced upon differentiation, and the associated switch from Myc-Max to Mad-Max heterocomplexes seem to repress genes normally activated by Myc-Max. We have identified two related mammalian cDNAs that encode Mad-binding proteins. Both possess sequence homology with the yeast transcription repressor Sin3, including four conserved paired amphipathic helix (PAH) domains. mSin3A and mSin3B bind specifically to Mad and the related protein Mxi1. Mad-Max and mSin3 form ternary complexes in solution that specifically recognize the Mad-Max E box-binding site. Mad-mSin3 association requires PAHS of mSin3A/mSin3B and the first 25 residues of Mad, which contains a putative amphipathic alpha-helical region. Point mutations in this region eliminate interaction with mSin3 proteins and block Mad transcriptional repression. We suggest that Mad-Max represses transcription by tethering mSin3 to DNA as corepressors and that a transcriptional repression mechanism is conserved from yeast to mammals. |
| Document Type: Article |
| Language: English |
| Reprint Address: AYER, DE (reprint author), FRED HUTCHINSON CANC RES CTR, DIV BASIC SCI, ROOM A2-025, SEATTLE, WA 98104 USA |
| Publisher: CELL PRESS, 50 CHURCH ST CIRCULATION DEPT, CAMBRIDGE, MA 02138 |
| Subject Category: Biochemistry & Molecular Biology; Cell Biology |
| IDS Number: QM399 |
| ISSN: 0092-8674 |